app crashes when thread with api request is quitted

Shubham Mandavkar

I want the thread to retrieve data from yfinance. but when the thread finishes its execution it crashes the application.

worker class :

class MyWorker(QObject):
    finished = Signal()
    def run(self):
        for i in range(15):
            stk = yf.Ticker('PNB.NS')
            hist = stk.history(period='1d', interval='1d')
            print(hist)
            time.sleep(1)
        self.finished.emit()

Thread creation:

        self.worker = MyWorker()
        self.myThread = QThread()
        self.worker.moveToThread(self.myThread)
        self.worker.finished.connect(self.myThread.quit)
        self.worker.finished.connect(self.worker.deleteLater)
        self.myThread.started.connect(self.worker.run)
        self.myThread.finished.connect(self.myThread.deleteLater)
        self.myThread.start()

SGaist

Hi and welcome to devnet,

Which version of PySide/PyQt ?
On which OS ?
How did you install it ?
Can you provide a complete minimal script that shows the behaviour ?

Shubham Mandavkar

@SGaist I am using PySide6 on window11 and installed PySide6 using python pip.
And when I comment the stk.history() line application works fine.

JonB

@SGaist said in app crashes when thread with api request is quitted:

Can you provide a complete minimal script that shows the behaviour ?

@Shubham-Mandavkar
Can you complete your sample with (as little as possible!) code to make a complete program for people to see/run, i.e. you have shown some "thread creation" but we ant to see exactly how/where it is invoked in a full program, and in class MyWorker we don't know what yf.Ticker() & stk.history() do, yet you tell us that without stk.history() call it does not crash so presumably that is relevant....

Shubham Mandavkar

@JonB yf is alias for yfinance and stk.history() returns the history of the stock from yfinance.
Below is the minimal code which you can run.

# This Python file uses the following encoding: utf-8
import sys
from PySide6.QtCore import  QThread, Signal, QObject
from PySide6.QtWidgets import QApplication, QMainWindow
import time
import yfinance as yf

# Important:
# You need to run the following command to generate the ui_form.py file
#     pyside6-uic form.ui -o ui_form.py, or
#     pyside2-uic form.ui -o ui_form.py 


class MainWindow(QMainWindow):
    def __init__(self, parent=None):
        super().__init__(parent)

class MyWorker(QObject):
    finished = Signal()
    def run(self):
        for i in range(5):
            stk = yf.Ticker('PNB.NS')
            hist = stk.history(period='1d', interval='1d')
            print(hist)
            time.sleep(1)
        print('thread finished')
        self.finished.emit()
     

if __name__ == "__main__":
    app = QApplication(sys.argv)
    widget = MainWindow()

    worker = MyWorker()
    myThread = QThread()
    worker.moveToThread(myThread)
    worker.finished.connect(myThread.quit)
    worker.finished.connect(worker.deleteLater)
    myThread.started.connect(worker.run)
    myThread.finished.connect(myThread.deleteLater)
    myThread.start()
    
    widget.show()
    sys.exit(app.exec())

gui does nothing. When thread completes its work the application automatically closes.

JonB

@Shubham-Mandavkar
Well, it still comes down top how yfinance behaves, since that is causing the problem. And I note they say

yfinance offers a threaded and Pythonic way to download market data from Yahoo!Ⓡ finance.

So one might assume there is some issue between their "threaded" use and your use of QThread?

Have you at least verified this works if you do not put it any QThread? And what does "crashes the application" mean, have you run it under a Python debugger or a system/C++ debugger to see if there is any cluse as to what might be the cause?

SGaist

Can you share how you created your Python environment ?

On macOS, with:

Python 3.12.0
PySide6 6.6.1
yfinance 0.2.33

No crash happened.